⚡ Aircraft Wire Gauge Reference
AWG wire gauge chart with conductor diameter, approximate ampacity, resistance, and typical aircraft wiring applications per AC 43.13-1B and MIL-W-22759 guidance.
| AWG | Diameter (in) | Diameter (mm) | Approx. Ampacity* | Resistance (Ω/1000ft) | Typical Aircraft Use |
|---|---|---|---|---|---|
| 28 | 0.0126" | 0.321 mm | 1–3 A | 65.3 | Signal wires, thermocouple leads, low-current instrumentation, avionics bus data lines |
| 26 | 0.0159" | 0.404 mm | 3–5 A | 41.0 | Low-current control circuits, indication lighting, small sensor signals |
| 24 | 0.0201" | 0.511 mm | 5–8 A | 25.7 | Avionics signal and data cables, pitot heat indication, cockpit lighting circuits |
| 22 | 0.0253" | 0.644 mm | 8–12 A | 16.1 | General aircraft control wiring, landing gear position indicators, door/proximity sensors |
| 20 | 0.0320" | 0.812 mm | 12–17 A | 10.2 | Very common in commercial aviation. General circuit wiring, lighting, valve control circuits, solenoids |
| 18 | 0.0403" | 1.024 mm | 17–25 A | 6.39 | Heavier control circuits, motor control, hydraulic valve actuators, landing lights feeders |
| 16 | 0.0508" | 1.291 mm | 25–35 A | 4.02 | Navigation lights, exterior lights, fuel pump circuits, windshield wiper motors |
| 14 | 0.0641" | 1.628 mm | 35–45 A | 2.53 | Pitot heat, heavier lighting loads, hydraulic pump motors, galley feeder circuits |
| 12 | 0.0808" | 2.053 mm | 45–65 A | 1.59 | Main bus feeders, APU control, fuel boost pump feeders, engine ignition circuits |
| 10 | 0.1019" | 2.588 mm | 65–90 A | 0.999 | Generator feeder circuits, heavier bus tie connections, main ground straps |
| 8 | 0.1285" | 3.264 mm | 90–120 A | 0.628 | Main battery cables (small aircraft), starter assist circuits, generator field feeders |
| 6 | 0.1620" | 4.115 mm | 120–165 A | 0.395 | Main distribution bus connections, ground power input circuits, heavy motor feeders |
| 4 | 0.2043" | 5.189 mm | 165–215 A | 0.249 | Battery cables on light turbines, ground power connections, APU starter feeders |
| 2 | 0.2576" | 6.543 mm | 215–280 A | 0.157 | Main battery connections on larger aircraft, engine starter cables, main ground returns |
| 0 (1/0) | 0.3249" | 8.252 mm | 280–365 A | 0.0983 | Main battery cables, engine starter cables on large turboprop/jet aircraft |
| 00 (2/0) | 0.3648" | 9.266 mm | 365–470 A | 0.0779 | High-current bus feeders, main power cables on transport category aircraft |
| 000 (3/0) | 0.4096" | 10.40 mm | 470–600 A | 0.0618 | Main power distribution, generator output cables on large transport aircraft |
* Ampacity values are approximate for single conductors in free air (MIL-W-22759). Bundled wire, conduit routing, and elevated temperatures reduce ampacity significantly. Always refer to the aircraft's wiring diagram manual (WDM) and AMM for certified ratings.
AWG Basics for Aviation
AWG (American Wire Gauge) numbers run inversely to diameter — smaller number = larger wire. Common aviation wire is made from stranded aluminum or copper conductors with PTFE, ETFE, or XL-ETFE insulation. MIL-W-22759/16 (PTFE) and M22759/34 (XL-ETFE) are among the most common specs on transport aircraft.
Wire Sizing Rules (AC 43.13)
- Size for current capacity and acceptable voltage drop
- Max voltage drop: typically 1V per 50 ft of wire run (varies by circuit)
- Never size a wire smaller than AWG 20 for cockpit/avionics circuits unless specifically approved
- Ground wires should be one size larger than the associated hot wire
- All wiring must be protected by a correctly-rated circuit breaker or fuse
Connector Backshell Compatibility
MIL-DTL-38999 (Series III), MS27508, and MIL-DTL-26482 connectors are common on transport aircraft. Contact size (size 22, 20, 16, 12, 8) determines the acceptable wire gauge range. Always verify wire-to-contact compatibility in the aircraft WDM or connector manufacturer data. Use the correct contact insertion/extraction tool to avoid connector damage.